Platinum coordination compounds have been used in cancer chemotherapy since the late 1960s. Cisplatin and carboplatin are the most common platinum based drugs used in cancer treatment. Pharmacokinetics investigations, the determination of the body burden during the treatment as well as the baseline levels of platinum in humans has attracted great interest. Thus, accurate analytical methods for fast and easy platinum monitoring in clinical samples are necessary. In the present work, atomic spectrometric methods for the direct determination of platinum as cisplatin and carboplatin in human urine were investigated. In relation to Graphite Furnace Atomic Absorption Spectrometry the optimum temperature program, sample volume and diluent concentration were defined by a central composite design optimization. Analyte addition with PtCl2 was used for calibration, and no statistically significant difference was observed between the results obtained by the proposed and comparative procedures in the analysis of a set of urine samples. Multiplicative matrix effects were overcome by adding NaCl to the diluent solution. External calibration with PtCl2 in blank matched medium was then possible. The recoveries were 100±1%, and the coefficient of variation ranged from 1 to 10%. The limit of detection (LOD) was 4 ug L-1 of Pt in the original urine sample. High resolution continuous source flame atomic absorption spectrometry was also investigated. The flame conditions were optimized by a multivariate D-optimal design, taking as response the sum of the analyte addition calibration slopes and their standard deviation. The LOD was 55 Og L-1 (n=10, k=3), in the original sample. Matrix matched external calibration with PtCl2, was possible, and the results obtained by the proposed procedure were also in good agreement with those obtained by independent comparative procedures.